Tow bale



Feb. 11, 1964 E. G. GUENTHER ETAL 3,

TOW BALE Filed June 19. 1961 EdgarGfiueniher Johnw Smith BY F INVENTORSI M. M P

which a crimp has been added.

United States Patent 3,120,893 T0?! BALE Edgar G. Guenther and John W. Smith, Kingsport, Tenn, assignors to Eastman Kodak (Iornpany, Rochester, N.Y., a corporation of New Jersey Filed .lnne 19, 1961, Ser. No. 120,461 3 Claims. (ill. 206-835) The present invention relates to the packaging of manmade fibers and yarn. More particularly this invention relates to the packaging and package of products of the continuous filament type that are formed into tow to This application is a continuation-in-part of our copending application 713,- 968, filed Feb. 7, 1958.

In the trade the word tow concerns a textile product where numerous ends of continuous filaments are brought together to form a ropelike strand, band or ribbon. The size of the tow has been from, for example, 80,000 to 2,000,000 total denier. It has been packaged as a ball warp. Further details concerning tow may be had by reference to our co-workers US. Patent 2,794,239. In the process of manufacturing tow, a crimp is imparted to the tow. This crimp is imparted to the tow in such a manner as to cause the tow to conform to a ribbon shape of rectangular cross-section, for example, & x 2" for the larger deniers.

The new method of packaging, according to the present invention, may be described as baled tow. The general concept is to direct the tow into a suitable baling press in such a manner as to form a square prism bale acceptable as a supply source for subsequent tow usage.

The present invention has as its principal object the provision of a new and improved tow bale.

Yet another object of the invention is the provision of a baled tow in which the tow is packaged under substantially zero tension so that there is no change in the crimp of the tow.

Still another object of the invention is the provision by which the tow is traversed in its passage to the baler to provide a uniform pattern in tow bales so that the tow may be withdrawn from the bale under low tension and without tangling.

And yet another object of the invention is the provision of a high density tow bale.

And another object of the invention is the provision of a tow bale in which the tow can be drawn from the bale without the use of creels or mandrels.

And still another object of the invention is the formation of a tow bale having a novel combination of high density, low denier per filament, and low total denier.

A further object of the invention is the provision of a bale of tow from which cigarette filters of superior tar removal efficiency may be readily prepared.

And a still further object of the invention is the provision of a tow bale whereby filament pull-ups in withdrawal of tow from the bale are lessened and the fiufiing of filaments in the withdrawal of the tow from the bale is substantially prevented.

Another object of the invention is the provision of a highly compacted tow bale of sufiiciently high density, low denier per filament and low total denier to avoid tangling and damage to the bale during handling and prevent loss of tow due to such damage. Other objects will appear hereinafter.

As is known in the industry and as mentioned above, a ball-warp arrangement of winding tow has been used whereby the ball warp is positioned in a cardboard container for shipping or delivering. Such an arrangement has been used in preparation of a tow package containing untwisted, elongate, continuous filament tow, for example of cellulose acetate, having a total denier of from about 3,120,893 Patented Feb. 11, 1964 80,000 to about 160,000, as described in our coworkers U.S. Patent 2,794,239. Such a package, however, is sometimes subject to entanglement of the tow as it is withdrawn therefrom or may be inconveniently bulky as well as more expensive than the bale of the present invention. Also, the problem still remains of how to package a tow of lower denier per filament and lower total denier of the type more recently used in the manufacture of tobacco smoke filters, particularly because of the interest in high tar removal. The tow should be removable from the bale without loss of the high and uniform crimp and without damage to the package.

After extended investigation we have discovered a package which will satisfy the foregoing requirements.

In the broader aspects of our invention we have found surprisingly that a tow of a denier per filament of less than 9 and a total denier of not greater than about 80,000 may be compacted into a bale of a density of at least 24 pounds per cubic foot and preferably higher, the tow being arranged substantially without tension in separate layers of uniform pattern in a more or less zigzag fashion. The tow, rather than being more difiicult to remove due to its highly compacted nature and its low denier per filament and low total denier, as might be expected, is not only readily removable from the bale but also upon removal will both retain its crimp and not become tangled. Also it permits a smaller number of plucks on the surface of the bale and filament pull-ups than are normally encountered in withdrawing tow from a package. A pluck is a group or cluster of filaments from a section of tow which has been fiurfed. due to filaments being disturbed by the withdrawing tow. Filament pull-ups refer to individual filaments from the tow of the adjacent layer or traverse being pulled up with the withdrawing tow.

We have also found that the tow may be removed from such a bale with practically no damage or waste and that thus a considerable saving may be obtained by avoiding loss because of damaged tow. By the use of tow withdrawn from a bale comprising a continuous strand of cn'mped tow, preferably having 717 crimps per inch, of a denier per filament of less than 9.0, a total denier of not greater than about 80,000, a density of at least about 24 pounds per cubic foot, and an arrangement substantially without tension in separate layers of uniform pattern, we obtain filter rods which exhibit enhanced tar removal. We have additionally found that the tow removed from a bale satisfying these prerequisites is a stronger tow which withdraws from the bale more readily than from the packages of the prior art and processes with less difficulty. The high crimp with little crimp variation which is important for cigarette filter tow is retained when the tow is withdrawn from out novel hole.

The novel tow bale of this invention may be produced by the method and apparatus described in our US. Pat ents 2,947,241 and 2,947,242, although the tow may also be compacted into the bale of this invention in other ways.

In order to prepare the tow prior to compacting in our novel bale we may proceed as follows. A spinning composition, e.g. of cellulose acetate having a 38-41% acetyl content of acetone or other suitable solvent, is made up. If round or cloverleaf shaped filaments are desired, the spinning solution is spun in accordance with the methods described in H. G. Stone US. Patent Nos. 2,000,047 and 2,000,048. If on the other hand filaments of a special cross section such as a Y cross section are desired, the solution may be spun in accordance with the method described in Raynolds et al. US. Patent No. 2,839,027.

In accordance with a preferred embodiment. of the tow prepared hereunder, the filaments would be dry spun 3,1 3 from high viscosity cellulose acetate through orifices of 030-045 mm. diameter at low draft. For example, using acetone solvent, the high viscosity ester is spun at about 55 C. at a draft of less than 1.8.

The filaments of whatever configuration, produced as aforesaid after removal of solvent and setting up in a spinning cabinet, may be conducted out of the cabinet around a godet roll. Prior to or beyond the godet roll the filaments may be treated with an appropriate lubri cant such as a sorbitan compound. After this 5,000 to 40,000 of the filaments are formed into a tow and have imparted thereto a uniform and regular crimp. This may be accomplished as follows:

Generally the number of filaments and the size tow are such that it is not convenient to produce the tow from a single large spinnerette and our preferred practice is to combine the threads from a number of spinning cabinets. 1000 to 5000 denier is an advantageous size to produce from a single cabinet, so 15 to 70 cabinets are combined to form a composite tow of, for example, 20,000 to 70,000 denier. The spinning capacity of the cabinet and the arrangement of the cabinets will to gether determine the number which can readily be combined to form the desired tow. Since the linear speed of all cabinet threads should be the same, the godet rolls may be driven from a common power source. So that each cabinet will produce its proportionate share of the total denier, each spinnerette may be supplied spinning solution from its own metering pump, and these may also be driven from a comon power unit. The godet rolls and metering pumps may both be driven by the same motor, or separate power units may be used, in which case they should be inter-connected electrically, hydraulically, or mechanically.

The threads from the required number of cabinets are drawn together to form the tow which is fed to a stuliingbox type crimper. To secure uniform crimp, it is important that the tow be presented to the crimper as a fiat band of uniform width and thickness. Variations cannot be tolerated, and it is equally important that the band width as the tow enters the crimper be properly correlated to the width of the rolls. Too narrow a band causes low crimp on the edges. Too wide a band results in what is termed crimper harsh. This occurs when a few filaments are trapped between the sides of the rolls and the side plates which form the stuffing box, the filaments thereby being chewed up and pressed into small, fiat flakes of the material from which the filaments were spun.

Following the crimping operation the tow is compacted into the novel bales of the instant invention.

For assistance in the further understanding of our invention reference is made to the attached drawing forming a part of the present application.

FIG. 1 is a perspective view of the finished tow bale of this invention, with a cutaway portion depicting an illustrative part of the inside of said bale.

In FIG. 1 tow bale is held in compressed form by a plurality of reinforcing bands or straps, which may be, forexample, steel or some other appropriate metal or alloy 12, some running lengthwise around the bale and others widthwise. For moisture-proofing, bale 10 is wrapped in a siutable fabric 14 lined with polyolefin sheeting 16. The zigzag uniform layers of tow are illustrated at 18.

FIG. 2 is another perspective view of the bale with the top open for illustrating the Zigzag positioning of the tow referred to above. hat is, this figure shows the pattern of one layer, the top layer, of the tow in the tow bale of our invention and illustrates the ease with which the tow may be withdrawn from the bale under low tension without tangling, appreciable filament pullups and plucks, or damage to the tow. The left end of the layer is shown connected to the underlying layer,

4 while the right end of the layer has a tag connected thereto to facilitate finding the free end of the tow in the bale.

In FIG. 2 the tow bale 20 contains tow distributed in superimposed layers 22 of uniform pattern. The tow is laid in a zigzag pattern of layers, the tow strip being folded upon itself at the edges of tne bale, as shown at 24. The end of the tow has attached thereto an identifying tag as to facilitate ready and easy location of the free end of the tow in the bale when the latter is opened by the user.

A still further understanding of our invention will be had from a consideration of the following illustrative examples.

Example I In a preferred embodiment of this invention, a continuous filament cellulose acetate tow (acetyl content about 39%) was compacted into two bales of 1.67 denier per filament (denier per filament is hereinafter referred to as D/F), 37,000 total denier (total denier is hereinafter referred to as TD) and 15 crimps per inch tow. The first bale was of a density of 23.4 pounds per cubic foot, the former weighing 636 pounds, and the latter weighing 784 pounds. The volume or" each of the bales was approximately 27.2 cubic feet. After aging for one week, tow from the bales was withdrawn through an 8" banding jet, over a fixed drum guide, through a pair of feed rolls, and then to an air doifer. Withdrawal speed of the tow was 300 feet per minute. One ten minute run was mane from each bale. Observations were made of differences in withdrawal characteristics and appearance of the bale surface. Filament pull-ups were more fre quent for the lower density bale, and occasionally the filaments would be pulled up to the banding jet. Upon completion of the ten-rninute run, the number of plucks on the surface or the bale was determined. The pluck count was as follows:

Bale density: No. of plucks 28.8 lbs/cu. ft 12 23.4 lbs/cu. ft 30 It is thought apparent from the foregoing that the higher density bale gave considerably less difficulty in processing, that is, withdrawing tow from the bale, the ease of withdrawal of tow being substantially greater as evidenced by the much smaller number of plucks in the tow removed from the higher density bale and the lesser degree of pull-ups.

When tow was removed from a bale of the same D/F and TD but of a somewhat lower density, one corner of the bale was disturbed, necessitating removal of several inches of tow before withdrawing the tow. This low-density tow was damaged somewhat during handling, as compared to the higher density bales, which exhibited substantially no damage. The 28.8 pounds per cubic foot bale exhibited a considerably smoother appearance than the 23.4 pounds per cubic foot bale.

Example 11 Two more cellulose acetate bales of the same respective densities but containing tow of a D/F of 8 and a TD of 60,000 were prepared and the ease of withdrawal of tow therefrom measured as in Example I. In the case of the lower density bale some entangling and 28 plucks were encountered. 'Iow was withdrawn from the bale of higher density with ease and no entangling. Only 15 plucks were encountered. The baled tow had 12 crimps per inch, and substantially no loss of cr-imps took place in the tow withdrawn from the denser bale. On the other hand, in the tow withdrawn from the lower density bale, flufilng and loss of crimp were noticeable.

Example III Two additional bales of tow were prepared as in Example I, with the exception that the tow had a D/F 0f about 1.6 and a TD of 37,000, and the former had a density of 23.0 pounds per cubic foot as compared to a density of 29.0 pounds per cubic foot for the latter. Tow was withdrawn from the bales at a speed of 300 feet per minute as in Example I. Again the higher density bale showed less pull-ups and considerably less plucks. It was also observed that the higher density bale exhibited substantially less tendency to be damaged during handling than the lower density bale. Tow from the higher density bale withdrew more easily than that from the lower density bale and with substantially no entanglement, as compared to some entanglement of the tow as it was withdrawn from the lower density bale.

Example IV A bale of tow of a density greater than 24 (26 lbs/cu. ft.) was compared with a bale of tow of a density of less than 24 (20.3 lbs/cu. it.) as in Example I. The D/F and TD of the tow were the same as in Example I. However, in this example continuous-filament polyvinyl acetate tow was used instead of cellulose acetate tow. Comparative results were similar to those of Example I. The higher density bale showed a pluck count of 15 as opposed to a pluck count of 28 for the lower density bale, and in withdrawing tow from the higher density bale considerably less pull-ups were encountered.

Example V Two bales of cellulose acetate continuous filament tow, the cellulose acetate having an acetyl content of 39.5%, were prepared. The only substantial difference in the tow of the two bales was that the lubricant used on the first was an emulsion lubricant and the lubricant used on the second was an oil lubricant. The following table gives the properties of the tow withdrawn from the two bales. Both tow bales had a density of 28.4 lbs./ cu. it.

The crimp (amplitude) was retained upon removal of the tow from the bale, and the breaking strength of the tow was excellent in both cases.

Example Vl Filter rods were produced from tow withdrawn from two separate bales of equal density coming within the scope of the present invention. The weight, pressure drop and other properties of the filter rods were measured. The following table shows the good tar removal properties of the filter rods as exhibited by the pressure drop.

1 Average weight in but without plasticizer 2 Pressure drop in inches of water for an air How of 17.5 ml. per sec. The tow removed from the bale at 300 ft./min. and formed into filters as above withdrew from the bale with ease and processed without difiiculty. The pressure drop is an important factor affecting the removal of tars, and the values obtained indicated excellent tar removal characteristics in the filter rods prepared. Again the above data exhibits the surprising nature of the ability to readily remove tow from our low-D/F, low-TD, high-density tow bale while still retaining the high crimp level and little crimp variation and permitting production of filters of enhanced tar removal emciency at high speed. The crimp of the tow removed from the bales used in the preparation of the cigarette filter rod of the above table was visually examined, and the high crimp retention was selfevident. A narrower range of breaking strengths was encountered than in tow removed from bales of lower density containing tow of higher TD and D/ F. The desirable characteristics of the filter rods of the above table accentuate further the advance in the art brought about by our high density, low-TD, and low-D/F tow bale. Prior to this invention a package from which the low-TD, low-D/F, highly crimped tow employed for high tar removal cigarette filters could be withdrawn substantially without entanglement or loss of crimp was unknown to the art. The significance of the data contained in the above table is further emphasized by the fact that, in tobacco smoke filters, pressure drop is inversely related to the filament denier, thus requiring lower-TD tows for reasonable pressure drop. Heretofore no satisfactory way for packaging such lower-TD tow was known. Also, to attain satisfactory firmness in the filter, high crimp is desirable.

grams of yarn, moisture, finish and paper wrap,

Example VII To demonstrate further advantages inherent in the processing of tow from the high-density, highly crimped, low-D/F, low-TD tow bale of this invention, several such bales were prepared, and a series of filter rods was made from tow withdrawn therefrom. Each bale had a density of about 28.4 lbs/cu. ft. As illustrated in the following table, the D/F was varied from 1.6 to 5 and the T D from 37,000 to 90,000. The speed of withdrawal was about 300 ft./rnin. for about 10 minutes in each case. The data in this table indicate that the rods prepared from the 90,000 TD exhibited a lesser hardness and low tar removal as compared with the baled tow of the present invention, in cigarette filters prepared therefrom.

Tow Lot No i. l 2 3 4 5 6 Denier per fil 1. 6 2. 1 3 5 5 5 Total Denier 37. 000 48, 000 50, 000 70, 000 70, 030 90, 000 Finish. Emulsion Emulsion Emulsion Emulsion Emulsion Oil Crimp pe 16 16 15 13 13 9 Length- 90 90 90 90 90 Circumference. 24. 8 24. 7 24. 7 21. 8 24. 8 24. 9 Weight, gins .611 0.706 760 889 1. 0&7 1.000 Pressure Drop, Rod 14. 6 l4. 3 12. 1 10. l 13. 3 9. 1 Pressure Drop, 15 mm i 2. 8 2. 7 2. 3 2.0 2. 5 1. 7

Tars Removal, percent 42 40 32 24 31 21 Hardness 1 8. 1 9. 4 6. 0 5. 6 3. 5 8. 0

1 Hardness is the deformation resulting from an arbitrary load. It is measured in units of 0.1 mm. and a small value indicated a hard rod.

The above results further demonstrate that tow from the novel high-density, low-D/F, low-TD bale of this invention can be processed into filter rods which have advantages over prior art filters. The high crimp permits fabrication of filters having a considerable variety of pressure drops, depending upon the filter or tar removal efficiency desired, from one tow. The more eilicient processing results in a higher degree of utilization of the tow, thus producing more high tar-removal filters from a given amount of material.

Example VIII A bale of polyethylene tow of a density of 26, a TD of 60,000 and a D/F of 3 was prepared using the apparatus and procedure such as described in US. Patents 2,947,241 and 2,947,242. Tow was withdrawn from the bale with ease and without entanglement at the rate of about 25 meters per minute for about one-half hour.

Example IX A bale of cellulose acetate propionate having an acetyl content of 3540% and a propionyl content of 0.5-5 was prepared as in Example Vlll, the density, TD, and D/F being the same as for Example VIII. The tow withdrawn from the bale at 25 meters per minute retained its uniform high crimp and did not become entangled. Withdnawal was continued for minutes.

From the foregoin examples the several advantages of the tow bale of this invention are readily apparent. The retention of crimp uniformity in tow removed from the bale increases the average breaking strength and reduces the range of the breaking strength. Entanglement is minimized, and better tow withdrawal and processing properties are obtained. More and better tobacco smoke filters can thus be produced from less tow. The bale of the present invention is advantageous in taking up less shipping space, storage space per thousand filters producible therefrom, than prior packaging. Also as pointed out above our bale is less susceptible to change from rough handling in shipping or moving around within the plant.

Although the invention has been described in considerable detail with reference to certain preferred embodiments thereof, it will be understood that variations and modifications can be effected without departing from the spirit and scope of the invention as defined in the appended claims.

We claim:

1. A generally rectangular bale of compressible material comprising a continuous strand of crimped continuous filament tow anranged substantially without tension in highly compacted form in separate layers of uniform Zigzag pattern, said tow having 7-17 crimps per inch, a

denier per filament of less than about 9.0 and a total denier of not greater than about 80,000, said tow bale having a protective cellulosic cover completely enclosing the surface thereof, said cover being plastic lined on the inside and said bare being encircled in two directions perpendicular to each other by spaced parallel bands forming acuate bulges therebetween, said tow being compacted to about 24 pounds or more per cubic foot and having an easibly removable tagged free strand end, said compacting to about 24 pounds or more per cubic foot giving a briclolike self-sustaining configuration of tow when the protective cover and bands are removed from the bale, which facilitates handy removal of said strand of tow from said bale.

2. A generally rectangular bale of compressible material comprising a lined cellulosic wrap completely encompassing said material, spaced parallel straps encircling said material and wrap both over the top and bottom and around the sides thereof, said material and wrap forming arcuate bulges between said reinforcing straps and between the last of said reinforcing straps toward the edges of said bale and said ends of said bale, said wrap being lined with a plastic polyolefin moisture-proofing barrier layer on the inside thereof, the compressible material in said bale comprising crimped continuous filament tow arranged in compacted layers imposed substantially without tension in a uni orm pattern to a density of about 24 pounds or more per cubic foot and wherein the said compacted tow is arranged in brick-like self-sustaining fashion, whereby said tow may be withdrawn from said bale retaining substantially all of the crimp and in good condition for immediate processing upon withdrawal.

3. The bale according to claim 2 wherein the moistureproof plastic barrier layer on the inside comprises polyethylene.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A GENERALLY RECTANGULAR BALE OF COMPRESSIBLE MATERIAL COMPRISING A CONTINUOUS STRAND OF CRIMPED CONTINUOUS FILAMENT TOW ARRANGED SUBSTANTIALLY WITHOUT TENSION IN HIGHLY COMPACTED FORM IN SEPARATE LAYERS OF UNIFORM ZIGZAG PATTERN, SAID TOW HAVING 7-17 CRIMPS PER INCH, A DENIER PER FILAMENT OF LESS THAN ABOUT 9.0 AND A TOTAL DENIER OF NOT GREATER THAN ABOUT 80,000, SAID TOW BALE HAVING A PROTECTIVE CELLULOSIC COVER COMPLETELY ENCLOSING THE SURFACE THEREOF, SAID COVER BEING PLASTIC LINED ON THE INSIDE AND SAID BALE BEING ENCIRCLED IN TWO DIRECTIONS PERPENDICULAR TO EACH OTHER BY SPACED PARALLEL BANDS FORMING ARCUATE BULGES THEREBETWEEN, SAID TOW BEING COMPACTED TO ABOUT 24 POUNDS OR MORE PER CUBIC FOOT AND HAVING AN EASIBLY REMOVABLE TAGGED FREE STRAND END, SAID COMPACTING TO ABOUT 24 POUNDS OR MORE PER CUBIC FOOT GIVING A BRICK-LIKE SELF-SUSTAINING CONFIGURATION OF TOW WHEN THE PROTECTIVE COVER AND BANDS ARE REMOVED FROM THE BALE, WHICH FACILITATES HANDY REMOVAL OF SAID STRAND OF TOW FROM SAID BALE. 